| Message ID | 20230626160834.696680-2-andrey.drobyshev@virtuozzo.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | block: align CoR requests to subclusters | expand |
On Mon, Jun 26, 2023 at 07:08:32PM +0300, Andrey Drobyshev via wrote: > This is going to be used in the subsequent commit as requests alignment > (in particular, during copy-on-read). This value only makes sense for > the formats which support subclusters (currently QCOW2 only). If this > field isn't set by driver's own bdrv_get_info() implementation, we > simply set it equal to the cluster size thus treating each cluster as having > a single subcluster. > > Signed-off-by: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com> > --- > block.c | 7 +++++++ > block/qcow2.c | 1 + > include/block/block-common.h | 5 +++++ > 3 files changed, 13 insertions(+) > > diff --git a/block.c b/block.c > index 0637265c26..4fe1743cfb 100644 > --- a/block.c > +++ b/block.c > @@ -6392,6 +6392,13 @@ int coroutine_fn bdrv_co_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) > } > memset(bdi, 0, sizeof(*bdi)); > ret = drv->bdrv_co_get_info(bs, bdi); > + if (bdi->subcluster_size == 0) { > + /* > + * If the driver left this unset, subclusters either not supported. s/either/are/ > + * Then it is safe to treat each cluster as having only one subcluster. > + */ > + bdi->subcluster_size = bdi->cluster_size; > + } Reviewed-by: Eric Blake <eblake@redhat.com>
On 6/26/23 18:08, Andrey Drobyshev wrote: > This is going to be used in the subsequent commit as requests alignment > (in particular, during copy-on-read). This value only makes sense for > the formats which support subclusters (currently QCOW2 only). If this > field isn't set by driver's own bdrv_get_info() implementation, we > simply set it equal to the cluster size thus treating each cluster as having > a single subcluster. > > Signed-off-by: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com> > --- > block.c | 7 +++++++ > block/qcow2.c | 1 + > include/block/block-common.h | 5 +++++ > 3 files changed, 13 insertions(+) > > diff --git a/block.c b/block.c > index 0637265c26..4fe1743cfb 100644 > --- a/block.c > +++ b/block.c > @@ -6392,6 +6392,13 @@ int coroutine_fn bdrv_co_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) > } > memset(bdi, 0, sizeof(*bdi)); > ret = drv->bdrv_co_get_info(bs, bdi); > + if (bdi->subcluster_size == 0) { > + /* > + * If the driver left this unset, subclusters either not supported. > + * Then it is safe to treat each cluster as having only one subcluster. > + */ > + bdi->subcluster_size = bdi->cluster_size; > + } > if (ret < 0) { > return ret; > } > diff --git a/block/qcow2.c b/block/qcow2.c > index e23edd48c2..94b8d0e1c2 100644 > --- a/block/qcow2.c > +++ b/block/qcow2.c > @@ -5197,6 +5197,7 @@ qcow2_co_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) > { > BDRVQcow2State *s = bs->opaque; > bdi->cluster_size = s->cluster_size; > + bdi->subcluster_size = s->subcluster_size; > bdi->vm_state_offset = qcow2_vm_state_offset(s); > bdi->is_dirty = s->incompatible_features & QCOW2_INCOMPAT_DIRTY; > return 0; > diff --git a/include/block/block-common.h b/include/block/block-common.h > index e15395f2cb..df5ffc8d09 100644 > --- a/include/block/block-common.h > +++ b/include/block/block-common.h > @@ -132,6 +132,11 @@ typedef struct BlockZoneWps { > typedef struct BlockDriverInfo { > /* in bytes, 0 if irrelevant */ > int cluster_size; > + /* > + * A fraction of cluster_size, if supported (currently QCOW2 only); if > + * disabled or unsupported, set equal to cluster_size. > + */ > + int subcluster_size; > /* offset at which the VM state can be saved (0 if not possible) */ > int64_t vm_state_offset; > bool is_dirty; Reviewed-by: Denis V. Lunev <den@openvz.org>
diff --git a/block.c b/block.c index 0637265c26..4fe1743cfb 100644 --- a/block.c +++ b/block.c @@ -6392,6 +6392,13 @@ int coroutine_fn bdrv_co_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) } memset(bdi, 0, sizeof(*bdi)); ret = drv->bdrv_co_get_info(bs, bdi); + if (bdi->subcluster_size == 0) { + /* + * If the driver left this unset, subclusters either not supported. + * Then it is safe to treat each cluster as having only one subcluster. + */ + bdi->subcluster_size = bdi->cluster_size; + } if (ret < 0) { return ret; } diff --git a/block/qcow2.c b/block/qcow2.c index e23edd48c2..94b8d0e1c2 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -5197,6 +5197,7 @@ qcow2_co_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) { BDRVQcow2State *s = bs->opaque; bdi->cluster_size = s->cluster_size; + bdi->subcluster_size = s->subcluster_size; bdi->vm_state_offset = qcow2_vm_state_offset(s); bdi->is_dirty = s->incompatible_features & QCOW2_INCOMPAT_DIRTY; return 0; diff --git a/include/block/block-common.h b/include/block/block-common.h index e15395f2cb..df5ffc8d09 100644 --- a/include/block/block-common.h +++ b/include/block/block-common.h @@ -132,6 +132,11 @@ typedef struct BlockZoneWps { typedef struct BlockDriverInfo { /* in bytes, 0 if irrelevant */ int cluster_size; + /* + * A fraction of cluster_size, if supported (currently QCOW2 only); if + * disabled or unsupported, set equal to cluster_size. + */ + int subcluster_size; /* offset at which the VM state can be saved (0 if not possible) */ int64_t vm_state_offset; bool is_dirty;
This is going to be used in the subsequent commit as requests alignment (in particular, during copy-on-read). This value only makes sense for the formats which support subclusters (currently QCOW2 only). If this field isn't set by driver's own bdrv_get_info() implementation, we simply set it equal to the cluster size thus treating each cluster as having a single subcluster. Signed-off-by: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com> --- block.c | 7 +++++++ block/qcow2.c | 1 + include/block/block-common.h | 5 +++++ 3 files changed, 13 insertions(+)